1. Field of the Invention
This invention relates to a method for separating a basic amino acid from a fermentation liquor, for example.
2. Description of the Background
Basic amino acids are conventionally obtained by separation from amino acid mixtures obtained by decomposing proteins. Currently basic amino acids are produced mainly by fermentation processes. However, in fermentation processes, neutral and acidic amino acids are producted as by-products and the removal of these neutral and acidic amino acids is always a significant problem. At present, the separation and/or removal of these by-product amino acids is generally effected by using a strongly acidic cation exchange resin.
Unfortunately, when using the ion exchange resin method, it is necessary to balance the yield of the basic amino acid and the rate of removal of the neutral and acidic amino acids. However, in industrial production, since reductions in the yield of the basic amino acid are to be avoided, much less of the neutral and acidic amino acids is removed than is desirable. Consequently, the ion exchange resin treated liquor is invariably and inevitably contaminated with such neutral and acidic amino acids. Unfortunately, these amino acids are a frequent cause of difficulty in recovering basic amino acid crystals from the ion exchange resin treated liquor.
Hence, a need clearly continues to exist for a method by which basic amino acids can be separated from a liquor containing the same and from neutral and acidic amino acids also contained therein, without compromising the yield of the basic amino acid.